New Insight into Progesterone-dependent Signalization

Abstract

Background: Various effects of steroid hormone activity cannot easily be explained by the action of classical nuclear receptors and genomic signal transduction pathways. These activities are manifested principally as rapid processes, lasting from seconds to minutes, resulting in changes in ion transduction, calcium intracellular concentration, and level of the second messengers, which cannot be realized through the genomic pathway. Hence, it has been proposed that other kinds of mediators should be involved in steroid-induced processes, namely receptors located on the cell surface. The search for their chemical nature and role is of utmost importance. Current state of knowledge confirms their relation to GPCRs. Moreover, it seems that almost every nuclear receptor specific for steroid hormone family has its membrane-bound equivalent. Objective: In this review, we summarize current state of knowledge about nuclear and membrane receptors for progesterone, and describe their potential functions alone, as well as in cooperation with other receptors. Conclusion: In the light of common expression, both in species and organs, membrane receptors could play a role that is at least comparable to nuclear receptors. Further exploration of membrane receptor-dependent signaling pathways could give a new insight in the treatment of many endocrine and oncological pathologies.